As world populations increase, the importance of agriculture in production of food supplies becomes ever more apparent. In a world of finite resources, an expanding population demands efficiency in use of these resources. This occurs at a time when environmental concerns have also pointed out problems with conventional agricultural methods.
Many factors are involved in growing an economically successful agricultural crop, since a proper blend of nutrients and water must be provided, as well as protection from insect pests, disease, and harsh environmental conditions. As a result, the success of a crop in an exterior, uncontrolled environment involves a degree of risk, and demands reliance on unpredictable factors. In order to reduce these risks, conventional farmers have come to rely on chemical fertilizers, pesticides and treatments for plant diseases which can, in themselves, produce unwelcome or unknown effects. The use of pesticides in commercial agriculture has led to the killing of non-target species due to concentrations of poisons in water run-off.
Even when artificial chemicals are not used, variations in rainfall or temperature can lead to environmental problems. In certain drought-stricken areas, low aquifer pressure has lead to salt water intrusion, which can cause environmental damage, as well as endanger crop yields. All of these problems in conventional agriculture result from crop production in what is largely an uncontrolled environment.
Conventional methods can also be very labor and cost intensive. As an example, in conventional methods of growing tomatoes in a field, the soil must first be cultivated by using tractors to disk the field. Herbicides may be applied to kill off competing plant growth, and fertilizers may be added to provide nutrients. The plants are then transplanted in the field, and may require staking as they grow larger, and pesticides may be applied to discourage tomato horn-worms, and other pests. If local rainfall is inadequate, watering or irrigation must be used periodically. Regular attention is required as the plant continues to grow and the fruits are harvested. As the plants start to bear fruit from the lower part of the stem, it is common practice to fold the lower parts of the stem down to the ground to allow more growing space on top. As the older, lower portion of the stem becomes brittle, the older foliage becomes unproductive and is increasingly susceptible to disease. The production of fruit usually takes 70-90 days. Harvesting the crop and transporting the fruit to the packing shed require much labor. A large amount of water is used, a large portion of which is lost due to evaporation and soil seepage. Effluent, as well as exhaust from trucks used to carry workers and harvest, can pollute the environment. Energy resources in the form of fuel and energy for pumps, etc. are used up in the process.
This process points out many deficiencies in conventional agriculture. It would be a great improvement if the plants would start producing earlier and harvesting could be done continuously without the use of manual labor, where reliance on risky environmental factors is reduced, where water and resource requirements could be reduced, and use of chemical herbicides, pesticides and fertilizers reduced or eliminated.
One prior art attempt to create a more efficient system for growing plants is found in U.S. Pat. No. 3,931,695 to Widmayer. This patent shows a method and apparatus for growing plants using artificial lights which are pulsed on and off at a rate which does not allow the plants to become overheated. It also discloses a scheme by which plant roots are woven into a movable belt which pulls the plant roots down into a nutrient solution, as the plant grows upward. Widmayer's invention, however, presents a very bulky mechanism in which the nutrient tank is not enclosed and would not be useable in low gravity conditions. Additionally, this system appears not to be designed for complete conservation and reuse of water, and some water loss through evaporation can be expected under terrestrial conditions.
Thus, there is a great need for an automated plant growing and harvesting system which can be used either in low or zero gravity, or in terrestrial conditions in which growing conditions can be maximized, environmental factors can be precisely controlled, and resources maximally conserved.